Diagnosing of High Voltage Power Supplies of Ion Pumps through Low Current Measurements

High voltage power supplies of ion pumps are widely used in numerous applications requiring ultra-high vacuum conditions. However, when they operate at very low pressures, determining their proper functioning becomes challenging. In this paper, a current measurement circuit is suggested, which includes two amplifiers and is well-suited for ion pump high-voltage power supplies. However, error-causing parameters in both amplifiers and resistors lead to inaccuracies in current measurement. Consequently, there is a limitation on the minimum measurable current, with its extent depending on the specifications of the circuit elements and the desired measurement accuracy. To evaluate the method’s feasibility, the proposed current measurement circuit undergoes modeling and analysis to quantify inaccuracies resulting from error-causing parameters in the current measurement. Subsequently, the minimum measurable current with the desired measurement accuracy using specific conventional amplifiers in the suggested circuit is calculated and experimentally validated under various conditions.